Geothermometry and geobarometry of overpressured environments in Qiongdongnan Basin,South China Sea*

We demonstrate the use of PVT fluid inclusion modelling in the calculation of palaeofluid formation pressures, using samples from the YC21‐1‐1 and YC21‐1‐4 wells in the YC21‐1 structural closure, Qiongdongnan Basin, South China Sea. Homogenisation temperatures and gas/liquid ratios were measured in aqueous fluid inclusions, and associated light hydrocarbon/CO₂‐bearing inclusions, and their compositions were determined using a crushing technique. The vtflinc software was used to construct P–T phase diagrams that enabled derivation of the minimum trapping pressure for each order of fluid inclusion. Through the projection of average homogenisation temperatures (155, 185.5 and 204.5°C) for three orders of fluid inclusion on the thermal‐burial history diagram of the Oligocene Yacheng and Lingshui formations, their trapping times were constrained at 4.3, 2.1 and 1.8 Ma, respectively. The formation pressure coefficient, the ratio of fluid pressure/hydrostatic pressure established by PVT modelling coupled with DST data, demonstrates that one and a half cycles of pressure increase–discharge developed in the Yacheng and Lingshui formations for about 4.3 Ma. In comparison, the residual formation pressure determined by 2D numerical modelling in the centre of LeDong depression shows two and a half pressure increase–discharge cycles for about 28 Ma. The two different methods suggest that a high fluid potential in the Oligocene reservoir of the YC21‐1 structure developed at two critical stages for regional oil and natural gas migration and accumulation (5.8 and 2.0 Ma, respectively). Natural gas exploration in this area is therefore not advisable.     

纸张液相脱酸效果主要影响因素及相应对策

纸张是传承中华文明的重要信息载体,液相脱酸法是应对纸张酸化并延缓纸张劣化的优选手段。事实证明,制备性质优良的脱酸液以高效去酸留碱并采用适宜工艺以保持纸张平整是实现优异脱酸效果的重要前提。本文对国内外近十年内多数液相脱酸工作进行调研,在此基础上从浸润性、分散性、加固性、抗菌性及防皱工艺五方面对纸张液相脱酸效果影响因素进行梳理并总结相应对策,为后续研究工作提供一定参考。     

Middle Ordovician (Darriwilian) conodonts from the Goldwyer Formation of the Canning Basin,Western Australia

Zhen, Y.Y., Normore, L.S., Dent, L.M. & Percival, I.G., 11 July 2019. Middle Ordovician (Darriwilian) conodonts from the Goldwyer Formation of the Canning Basin, Western Australia. Alcheringa 44, 25–55. ISSN 0311-5518

Middle Ordovician conodonts attributed to 46 species were recovered from a stratigraphic interval spanning the Willara, Goldwyer and Nita formations in core sections from the Sally May-2 and Theia-1 petroleum exploration wells in the Canning Basin, Western Australia. The Histiodella serrata, Histiodella holodentata and Eoplacognathus pseudoplanus biozones are recognized in the lower and middle part of the Goldwyer Formation, indicative of an early–middle Darriwilian age. This revised conodont biostratigraphy enables more precise correlation with North America and North and South China. Several biogeographically distinctive conodont species, most likely of North Chinese origin, are recorded from the Goldwyer Formation. Their presence signals a strong palaeobiogeographic connection between the Sino-Korean Craton and the Canning Basin on the western margin of eastern Gondwana during the late Middle Ordovician.

Y.Y. Zhen* [yong-yi.zhen@planning.nsw.gov.au], W.B. Clarke Geoscience Centre, Geological Survey of New South Wales, 947–953 Londonderry Road, Londonderry NSW 2753, Australia; L.S. Normore [leon.normore@dmirs.wa.gov.au]; L.M. Dent [louisa.dent@dmirs.wa.gov.au], Department of Mines, Industry Regulation and Safety, Mineral House, Geological Survey of Western Australia, 100 Plain Street, East Perth, WA 6004, Australia; I.G. Percival [ian.percival@planning.nsw.gov.au], W.B. Clarke Geoscience Centre, Geological Survey of New South Wales, 947–953 Londonderry Road, Londonderry NSW 2753, Australia;     

Early Carboniferous Siphonodella (Conodonta) faunas from eastern Australia

Early to Middle Tournaisian conodont faunas with Siphonodella from ten sections in eastern Australia, between Gloucester in New South Wales and Rockhampton in Queensland, may be referred to the following ‘standard’ zones; 1 sulcata, 2 upper duplicata, 3 sandbergi, 4 lower crenulata and 5 isosticha-upper crenulata, in ascending order. In eastern Australia the first occurrences of Gnathodus cuneiformis, G. delicatus, G. typicus and Protognathodus cordiformis, near the base of the lower crenulata zone, are significantly earlier than in Europe and North America. Consequently the base of the isosticha-upper crenulata zone in eastern Australia is defined by the first appearance of G. punctatus rather than that of G. delicatus. On the present evidence it is difficult to reconcile some brachiopod and conodont occurrences in the Early-Middle Tournaisian of eastern Australia.

Seventeen discrete conodont species are discussed, four of which are described informally: Dinodus sp. nov. A, Dinodus sp. nov. B, Pinacognathus sp. nov. A, and a species of Siphonodella transitional between S. cooperi and S. crenulata.     

Shell beads from Mississippian sites in the northern Yazoo Basin,Mississippi

ABSTRACT

In this paper, which focuses on the Mississippian period in the northern Yazoo Basin, Mississippi, I present some interesting findings from research done over the past century. In this area, most shell beads come from surface collections, or from excavated burials in cemeteries or ossuaries. Burial styles include extended, flexed, semi-flexed, and bundles, with very few cremations having been encountered. Bead burials also seem to reflect both common and elite people, and there are some interesting discoveries concerning association of shell beads. I will use 33 archaeologically investigated major sites as examples to illustrate an unexpected paucity of shell beads and other shell ornaments at some of the most heavily populated Mississippian sites in the Lower Mississippi Valley. Two other sites with shell beads in the uplands will be used for comparison.     

高质量发展背景下黄河流域中下游绿色生产率时空分异研究

高质量发展背景下，以绿色全要素生产率（GTFP）视角考察黄河流域中下游各地市2003—2018年间的经济发展质量。首先，对GTFP进行测度并与传统TFP比较分析；其次，对GTFP增长率的内在动力进行解构；最后，采用变异系数和回归分析检验GTFP的收敛趋势，并验证其增长率的影响因素。结果表明：①GTFP较传统TFP表现出“中部塌陷”为特征的非均衡分布；②2003—2013年间，技术效率的提升是GTFP增长的主要推动力，2013年后技术前沿水平转变为主要动力；③在“追赶”效应下，各地市GTFP的差异呈缓慢缩小趋势；④该区域GTFP的提高受产业结构、财政科技投入等因素的显著影响。     

高质量发展视角下黄河流域城市网络的结构演变与影响因素研究

城市作为人口、产业等要素聚集地，基于多要素解构城市网络对明确城市高质量发展的内涵具有重要作用。本文通过修正经典引力模型和社会网络方法，分析了高质量视角下黄河流域城市网络结构演变特征，利用QAP方法探求其影响因素。结果表明：(1)黄河流域城市网络基本形成了以郑州、西安、济南、太原、兰州等省会城市为核心，辐射至周边城市的网络结构，网络密度逐渐增大但整体较低，网络通达度相对较高且稳定。(2)城市网络社群内部关联高于社群间关联，说明高质量发展视角下黄河流域城市网络社群溢出效应主要以社群内溢出为主，社群外溢作用较少。(3)区位条件、交通基础设施、产业结构、政府支持强度、科技创新的差异对黄河流域高质量发展的城市网络演变有显著影响。